New cardiac troponin assay improves diagnosis and outcomes of acute coronary syndrome

28th November 2023

Use of a high-sensitivity cardiac troponin I assay in emergency departments can improve diagnosis for one in five patients who have acute coronary syndrome, according to new research led by the University of Edinburgh.

The assay also helped doctors to better diagnose and treat these patients, reducing death and future myocardial infarction in this group by almost 10% after five years compared to those who received the older, less sensitive test.

The researchers also found that while the new cardiac troponin assay led to improvements for patients with myocardial infarction, those who benefitted most were patients with a heart muscle injury caused by conditions such as heart failure, heart valve conditions and heart arrhythmias.

Published in the BMJ and funded by the British Heart Foundation, the researchers conducted a secondary observational analysis of the High-Sensitivity Troponin in the Evaluation of patients with suspected Acute Coronary Syndrome (High-STEACS) trial.

High-STEACS used a high-sensitivity cardiac troponin assay to improve precision at very low concentrations and improve the diagnosis and risk stratification of patients with suspected acute coronary syndrome.

While these assays are increasingly being adopted worldwide, little is known about their impact on patient outcomes.

For the secondary observational analysis, researchers studied the results for nearly 50,000 people who arrived at 10 emergency departments across Scotland with a suspected acute coronary syndrome between 2013 and 2016. They used routinely collected health record data and the data service DataLoch to follow up all participants for five years.

The primary outcome was any myocardial infarction or all-cause death at five years.

Secondary outcomes were any myocardial infarction; coronary revascularisation; all-cause death; cardiovascular death; cardiac death; and hospital admission for heart failure, ischaemic stroke, and major haemorrhage.

Over 10,000 patients had high troponin levels indicating heart injury using the new cardiac troponin assay, with one in five of these patients only identified by this high-sensitivity assay.

The researchers also observed that improvements in outcomes at five years were greatest in those patients with an index diagnosis of non-ischaemic myocardial injury.

Dr Ken Lee, clinical lecturer in cardiology at the University of Edinburgh, and the lead author of the study, said: ‘In the past, clinicians could have been falsely reassured by the results of the less sensitive troponin test, discharging patients that appeared to not have heart disease.

‘This new high-sensitivity test is the tool they needed, prompting them to look deeper and helping them to identify and treat both heart attacks and less obvious heart problems. In our trial, introducing this test led to an impressive reduction in the number of future heart attacks and deaths seen in this at-risk group.’

Professor Sir Nilesh Samani, medical director at the British Heart Foundation, added: ‘Medical professionals in emergency departments need the most efficient and accurate tools to look after people. This particularly applies to those who arrive with a suspected heart attack. Such a time-sensitive and life-threatening condition requires the very best diagnostic tests.

‘It is very encouraging to see that the new test trialled here is better at predicting long-term outcomes for these patients, whether they had a heart attack or a different kind of heart injury. This can lead to improved care for such patients.’

The new high-sensitivity cardiac troponin assay has been rolled out to emergency departments across the UK, and the researchers hope that more people will receive the specialist heart care they need to avoid more serious events in the future.

High cardiac troponin level associated with increased mortality risk

11th August 2023

Elevated levels of cardiac troponin in those for whom there was no clinical indication for testing is independently associated with medium-term cardiovascular and non-cardiovascular mortality, according to a large study by researchers at the University of Southampton, UK.

Cardiac troponin (cTn) concentrations above the manufacturer recommended upper limit of normal (ULN) and without a clinical presentation consistent with type 1 myocardial infarction, has been linked to a 76% higher risk of death, the study found.

The prospective, observational study, published in the journal Heart, was designed to assess the relationship between medium-term mortality and cTn concentration in a large consecutive hospital population, regardless of whether there was a clinical indication for performing the test.

It‘s rationale was based on prior research showing how increased cTn levels were associated with an increased mortality risk. For example, even among patients with dyspnoea and without a cardiac cause, there is a three-fold higher risk of death when cardiac troponin levels are elevated.

Cardiac troponin levels and mortality

The study included 20,000 hospital patients over the age of 18 years who underwent a troponin blood test for any reason between June and August 2017 at a large teaching hospital, regardless of the original clinical indication. Their average age was 61 and 53% were women.

In 91.4% of these patients, there was no clinical indication for cardiac troponin testing.

The mortality was significantly higher if the cTn concentration was above the ULN (45.3% vs 12.3% p < 0.001 log rank). Using multivariable Cox regression analysis, the log₁₀ cTn concentration remained independently associated with mortality (Hazard ratio, HR = 1.76, 95% CI 1.65 – 1.89).

In addition, multivariable analysis revealed a significant and independent association between the log₁₀cTn concentration with non-cardiovascular (HR =1.99, 95% CI 1.861 – 2.118) as well as cardiovascular mortality (HR = 2.53, 95% CI 2.198 – 2.90).

The researchers concluded on how ‘a snapshot cTn in a hospital population may represent a biomarker of overall medium-term mortality’.

Elevated cardiac troponin in acute dyspnoea possible marker of poor prognosis

4th May 2023

Raised cardiac troponin in acute dyspnoea could be a useful prognostic marker in those without an acute myocardial infarction (MI).

Acute dyspnoea is a common complaint within an emergency department (ED). Dyspnoea is also a common symptom of an acute myocardial infarction (MI), affecting nearly two-thirds of patients. This consequently necessitates prompt patient assessment.

High-sensitivity cardiac troponin T (CTT) can quickly assess patients with chest pain to rule out an MI. Nevertheless, elevated cardiac troponin T levels can also occur in those experiencing chest pain without an MI.

In the current study, researchers set out to determine role of CTT in ED patients presenting with acute dyspnoea not due to an acute MI. Adult patients with acute dyspnoea were included and CTT levels measured together with their clinical history. CTT levels were divided into three levels: <15, 15-100 and >100 µg/l. An analysis provided the three-month relative risk of mortality with adjustment to models for a patient’s clinical history.

Cardiac troponin and three-month mortality risk

A sample of 1001 patients had usable data. With CTT levels < 15 set as the reference point, a CTT level between 15 and 100 gave rise to a more than three-fold higher mortality risk (Hazard ratio, HR = 3.68 (95% CI 1.72-7.84). The mortality risk was even higher with levels above 100 µg/l (HR = 10.523, 95% CI 4.46-24.80).

Patients with higher cardiac troponin levels were generally older, had a higher number of co-morbidities and more severe symptoms. The researchers felt that the data highlighted the value of CTT as an important risk factor in acute dyspnoea without a cardiac cause.